Air compressor



June 23, 1942- P. SAPPINGTON AIR COMPRESSOR Filed Oct. 7, 1941 0 6 7 6 a m a 2 13 w 2 Z i 1/ w 3 p42 6 3 4 III 2 l 1! 0 W w m a M /V///////////////////// 1 P. sa ingtm, INVENTOR.

Patente d June 23, 1942 UNHTED STATES ATENT OFFICE AIR COMPRESSOR Paul Sappington, Los Angeles, Calif.

Application October 7, 1941, Serial No. 414,015 1 Claim. (01. 230-174) This invention relates to an air compressor, one of the objects being to provide a new and novel assembly of parts whereby friction is reduced to the minimum and the compressor thus rendered more efficient.

A further object is to provide a compressor utilizing a stationary piston and a reciprocating cylinder, the cylinder being supported and actuated by a connecting element pivotally joined thereto and driven directly by the crank-shank.

A further object is to provide a compressor which is kept cool by air which is caused to enter and discharge through the stationary piston.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claim, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

In the accompanying drawing the preferred form of the invention has been shown in section, only a part of the compressor casing and shaft being illustrated.

Referring to the drawing by characters of reference, l designates a portion of the housing of the compressor and mounted for rotation in this housing and suitable for bearings provided therefor is a shaft 2 having one or more cranks 3. Casing or housing I has an opening 4 in which is snugly fitted the upper end portion of an outer tubular piston 5. An annular flange 6 is provided on the end of this piston and bears against the housing or casing l as shown. A recessed head 1 overlies the flange and is secured thereto and to the housing I by bolts 8 or the like. This head is recessed as at 3 to provide a discharge chamber having an outlet In, said chamber being in communication withthe interior of the outer piston 5 as shown.

A tubular inner piston II is concentrically arranged within the outer piston 5 and spaced therefrom to form an annular outlet passage l2 and one end portion of this inner piston is extended through the head I and suitably secured thereto as by means of a nut l3 fitted tightly against the head and engaging threads M on piston H. The other end of the piston II has a tubular valve casing l5 screwed thereinto and projecting beyond the adjacent end of piston I I. The corresponding end of the outer piston 5 is counterbored as shown at IE to provide an enlargement of the outlet chamber l2 and this counterbore I6 is closed by an annular flange l1 forming a part of the valve casing l5 and provided with an annular series of ports l8. A valve ring I9 is held normally pressed against flange I! by a coiled spring 20 which thus acts as a check valve to permit air to flow through the ports IB into chamber I2 but prevents air from flowing in the opposite direction.

That end of the valve casing I5 surrounded by flange H is recessed to provide a valve seat 2| and this seat is normally engaged by a valve 22 having a stem 23 slidably mounted within a spider 24 or the like. A spring 25 extends around the stem 23 and bears at one end against a head 26 on onstem 23 and at its other end against the adjacent end portion of the Valve casing I5 so that valve 22 is thus held normally yieldingly in position to close outlet ports 21 which open into the casing [5.

A cylinder which is open at one end and closed at its other end has been indicated at 28 and is fitted on and adapted to reciprocate relative to the outer piston 5. Suitable packing rings 29, which can be carried by the outer piston 5, constitute means for preventing leakage of air between the cooperating surfaces of the parts 5 and 28. Obviously the pistons thus constitute a closure for cylinder 28. That end portion of the cylinder which constantly surrounds the piston 5 has diametrically opposed alined trunnions 30 which are journalled in bearings 3! provided in the free end of a forked connecting rod 32. The shank portion 33 of this connecting rod is engaged and actuated by the crank 3 and it is to be understood that the forked portion of the connecting rod is so proportioned as to permit the cylinder 28 and the connecting rod to swing relative to each other without coming into contact except at the bearings 3| where the trunnions are supported.

In practice the shaft 2 and crank 3 when rotated will cause reciprocation of thecylinder 28 While the connecting rod both reciprocates and oscillates. As the connection between rod 32 and the cylinder 28 is about an aXis extending diametrically through the cylinder, it will be obvious that as the cylinder is reciprocated, it is relieved of all thrust except along a straight; line and coaxially with the pistons 5 and H. During the movement of cylinder 28 toward the shaft 2 a. supply of air to be compressed is sucked into the cylinder from the inner piston I I through ports 21, it being understood that valves 22 will open under the pressure exerted by the inflowing air. When the cylinder 28 is moved in the opposite direction, the air which has thus been supplied thereto will be compressed and forced through ports I8 against the action of the ring valve [9 which will be unseated so that the compressed air thus will be permitted to flow into the discharge chamber I2, through chamber 9 and thence to outlet I0. As the air while flowing into and. out of the compressor passes through those portions of the pistons surrounded and engaged by cylinder 28, it will be apparent that this rapidly flowing air will serve as a medium for keeping down the temperature of the parts which are in frictional engagement.

What is claimed is:

In an air compressor the combination with a housing having an opening and a crank shaft mounted for rotation in the housing, of an outer tubular piston supported on the housing and extending thereinto through the opening, a head overlying and clamped upon the housing and a portion of the outer tubular piston, means for binding the parts together, said head providing a discharge chamber therein and having an opening, an inner piston extending through and engaging the wall of the opening, said inner piston being tubular and spaced from and concentric with the outer piston, a valve casing removably seated in the lower end of the inner piston, an annular flange thereon bridging the space between the valve casing and the outer piston and apertured to provide outlets, a spring-pressed valve normally closing the outlets against pressure of air from between the pistons, a springcontrolled valve normally closing the valve casing against pressure from without the pistons, a cylinder closed at one end and open at its other end, said cylinder being fitted snugly about and slidable along the outer piston, and a pitman connection between the cylinder and the crank shaft.

PAUL SAPPINGTON. 

